Hooke's Law

Question 1

State in words Hooke’s Law

Answer 1

when a spring is stretched elastically, force will be directly proportional to extension

Question 2

Give Hooke’s Law as an equation

Answer 2

F=kx

Question 3

what material property is given by the spring constant k?

Answer 3

stiffness

Question 4

how do you find the value of k from a graph of force against extension?

Answer 4

k is the gradient, so k=change F/change x

Question 5

what are the units for k and what does the value of this constant physically mean?

Answer 5

Nm^-1
if k=10N/m, then for 1m of extension, 10N of force will need to be applied

Question 6

what’s the formula for spring constant when springs are in series?

Answer 6

1/k(total) = 1/k(1) + 1/k(2) + 1/k(3), etc

Question 7

what’s the formula for spring constant when springs are in parallel?

Answer 7

k(total) = k1 + k2 + k3, etc

Question 8

explain how you use the f/x graph to find the spring constant k of the different arrangements of springs

Answer 8

gradient (in the linear portion of the graph)

Question 9

explain how you find the elastic potential energy stored in the stretched spring from the f/x graph

Answer 9

area under the graph

Question 10

give the equations for elastic energy stored in a stretched spring that follows Hooke’s Law

Answer 10

E(el) = 0.5Fx
E(el) = 0.5kx^2

Question 11

if the force acting on a spring is doubled, what happens to the energy stored in the spring?

Answer 11

it’s also doubled

Question 13

What feature of the graph shows it obeys Hooke’s law?

Answer 13

Straight line through the origin/force directly proportional to extension